Identification

Title

Separation of the lapse rate and the cold point tropopauses in the tropics and the resulting impact on cloud top-tropopause relationships

Abstract

Four years of temperature profiles from Constellation Observing System for Meteorology, Ionosphere, and Climate GPS satellite retrievals are used to examine the difference between the World Meteorological Organization lapse rate definition and the cold point definition of the tropopause in the tropics. The separation between the cold point tropopause (CPT) and lapse rate tropopause (LRT) heights is quantified in seasonal averages and with the frequency of occurrence. In seasonal averages, small separations, <0.5 km, are found in the deep tropics, increasing to ~1 km toward higher latitudes and maximizing at ~1.5 km near the jet streams. The seasonal average separations show significant longitudinal structures in the December-January-February (DJF) and June-July-August (JJA) seasons. Case studies indicate that breaking Rossby waves and their effects extending into the equatorial region are responsible for the longitudinal structure in the DJF season. The seasonal average CPT-LRT separation therefore identifies the regions of the tropical upper troposphere-lower stratosphere that are controlled by extratropical forcing. Examination of individual profiles shows that a small yet significant fraction (~12%) of temperature profiles has CPT-LRT separations of 1 km or larger in the region of small seasonal average separation. These large separations are produced by wave perturbations of the upper tropospheric temperature structure. The impact of tropopause separation on the cloud top-tropopause relationship is examined using colocated CALIPSO cloud top data. We find that the frequency of clouds above the tropopause is reduced by approximately 50% if the CPT is used instead of LRT. The occurrence of clouds above the CPT is nevertheless significant, especially over the western Pacific in the DJF season and over the Asian monsoon region in the JJA season.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7bp03r7

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2014-07-16T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact